Sometimes, not all the time, ill hear a random rattling noise that almost sounds like maybe spark knock? Thats the closest thing to the sound i can think to compare but it will do it for a few seconds and generally reving the engine makes it stop but usually it never does it at all and then sometimes it will, sounds as if its coming from the drivers side... not sure what it could be

 

I am just trying to figure out exactly where you think the noise is coming from. Is it coming from the engine bay?

 

Good luck finding an answer over the interwebz... its a cobalt, lots of rattles

 

Sounds like starving lifters.

 

Maybe? Sometimes it sounds like its coming from where the cai is but all i can honestly say is it's on the passenger side around engine bay somewhere.... starving lifters?

 

The oil takes a minute to lube up the lifters from a cold start. Does it sound like a knock at idle, but goes away when you rev until it goes back to idle where the sound may or may not come back, where it starts a real audible clicking noise again?

 

Yes that's it

 

When's the last time you changed the oil? I would do a seafoam to clean up some things that may be blocking oil from getting to your lifters.

 

Hsd the car 2 months bought it oil was changed before i got it the sticker from dealer says it needs it in 200 miles i bought oil and eveythinf to change it this weekend

 

Before this weekend, I would buy a bottle of seafoam, pour 1/3 of it into the crank case.
I did this when I had the said noise, and I think it remedied it, otherwise it was just a huge coincidence.

 

Never messed with sea foam before it just cleans it out basically?

 

Yeah, lots of people on this forum swear by it. Myself included - Sea Foam Motor Treatment | Sea Foam Sales Company

Probably like $8 at your local auto store.

 

I know this is old but did seafoam fix the problem?